Most radio-station ratings available to the public are general, giving a sense of the outlet's overall performance -- like these, for instance. But a radio insider has provided us with numbers specifically for the 5 a.m.-9 a.m. time period -- morning drive, the most lucrative of all the day parts. By that measure, KHOW's Peter Boyles isn't just beating the competition, but crushing it. And there are plenty of other intriguing revelations in the figures on view below.

The first page here features the top twelve, with digits from the June 2011 ratings period (the most recent) for listeners age twelve and over highlighted. Categories include average share (the percentage of those listening to radio in the market who are tuned to a particular station), cume persons (the number of different people who tune to a station during the day part for at least five minutes) and weekly TSL (the amount of time each week a person listens to the station).

It's difficult to simplify the totals -- to say how many people each share equals, for instance -- because of fluctuating listenership and a slew of other factors. And the math can get tricky. Consider that one station may actually have fewer listeners than one rated below it because those who do tune in listen for a longer period of time -- one reason why the weekly TSL figure is so important.

A commenter on a December blog post about ratings wrote that "based on things I've seen, top morning shows in Denver have somewhere in the ballpark of 150,000-200,000 listeners per week (and that's people who listen at least five minutes, no necessarily the full show)." This is as good an estimate as any.

Fortunately, the horse race is easier to comprehend. And among listeners age twelve and over, KHOW earned a 9.0 share in June, while second-place finisher KYGO-FM registered a 6.1 share -- a huge gap. One reason is Boyles's loyal listenership. His weekly TSL is three hours and fifteen minutes, tied for second overall, and behind just one other station in the top twelve -- KEZW-AM, which finished in eighth position largely because its fans tuned in for a whopping four hours and six minutes.

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Among the next twelve finishers, note the strong performance of Colorado Public Radio, which wound up thirteenth -- well ahead of many commercial outlets. Also impressive: little engine that could KTCL, which actually scored higher than higher-profile Clear Channel sister stations like KBPI-FM and KPTT-FM.

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Stations 25 through 36 are highlighted by KKFN-FM/The Fan, whose numbers in June were half of what it generated in February, during the height of basketball and hockey season, and KUNC, whose numbers are on the rise even though it's based in Greeley, and therefore not officially a part of the Denver-Boulder market.

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By stations 37 through 48, the numbers are falling off fast, with several registering a zero share. That doesn't mean no one is listening, but that mighty few are being tallied. Consider KCKK-AM, which scores a cume persons number of 29. But at least those folks are listening for 42 minutes a week.

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All the stations seen next are listed as tied for 44th place in the market, because all of them have a zero rating -- and most don't show any cume persons, either. Again, that doesn't mean no one's out there. Still, it suggests that the assorted streaming stations, as well as HD stations affiliated with prominent outlets like Alice, the Mountain and KBPI, haven't managed to accrue much of an audience.

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And that goes for this last batch, too. Zero share points, zero cume persons, zero time spent listening. Ouch.